MPL1 mineral plaster primer is specially formulated to manage high suction backgrounds while remaining vapour permeable. Ideal for consolidating problematic surfaces and substrates, MPL1 features a coarse-grit finish that provides a strong key for bonding new plaster. Proudly, MPL1 is the only plaster primer to have been independently tested for vapour diffusion, giving you confidence that water vapour will not become trapped within your building structure.
MPL1 is a VOC-free, odourless, water-based primer that is certified vapour permeable and eco-friendly. Made from natural minerals and water glass, it contains no co-binders such as solvents, gypsum, or cement, ensuring a non-hazardous application. Available in 7kg and 16kg UN-certified containers, MPL1 plaster primer is ideal for environmentally-conscious construction and renovation projects.
Common substrate types include:
- Masonry backgrounds
- Magnesium silicate boards
- Historic or new plasters such as lime, cement, or gypsum
- Stone
- Wood/wood-based boards
- Terracotta, some ceramic tiles, and paints.*
- A Lime Green in-house bond-strength testing facility is available for specific requirements.**
Preparation
- Ensure substrates are clean, dry, and free of loose material before application.
- Test a small area with your specific materials to check compatibility beforehand*.
- Avoid using on contaminated surfaces, in extreme environments, or under unusual conditions.
- Do not store or operate in temperatures below 5 °C or above 30 °c.
- Protect nearby surfaces, especially glass.
- Store in airtight containers and use within 12 months.
Application
- Stir well before use.
- Apply with a broad brush, using short strokes and ensuring the grit is evenly spread across the surface (see typical spread pattern on the left).
- The surface to be primed must be sound and dry.
- Where the surface is powdery or friable, work the primer into the affected areas with a brush and test for bond strength after 24 hours.
- Silic8 vapour open liquid primer penetrating solution (PS1 or PS2) is recommended before application on problematic or highly adsorbent surfaces.
- Allow to cure for 2-24 hours, depending on temperature and applied thickness.
- Appropriate vapour-open plasters can be applied at any time after 24 hours, and MPL1 has fully cured.
- Ensure that the plaster is appropriate to the task.
Coverage
On an even surface, 600 grams of MPL1 will cover approximately 1m² (7kg will cover approximately 12m²). Allow more for uneven surfaces.
Aftercare
- Allow the surface to dry completely before applying additional layers, plaster coverings, or decorations.
- Wash splashes, tools, and brushes with water after use.
- Dispose of any excess material following your local regulations (EWC 06 02 99).
- Cleaned tins can be fully reused and recycled.
Technical Information
- pH value in liquid state: pH 11.1
- Odourless
- Dries off-white
- Non-hazardous
- No VOC’s
- Application rate varies according to use; approximate spread rate 600g/m² on a flat, even surface.
- Storage life (unopened tins): 36 months if kept well sealed (protect from frost, moisture, and temperature extremes).
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* - We (Celtic Sustainables LTD, and Lime Green), are not responsible for compatibility with any substrates, whether listed or not. Substrates should be tested for suitability before use, and we accept no liability for such tests. We also disclaim any liability for misuse, failures outside our control, or consequential losses of any kind.
** - Lime Green charges a fee for this service, which provides only an estimate of the bond strength. Not all substrates can be tested at their facility. Because substrate types vary, it's recommended to test a representative area of the substrate to ensure it meets all your needs.
